/Engine/Source/Runtime/Engine/Public/LightSceneProxy.h
whether a scissor rect is set
virtual bool SetScissorRect ( [FRHICommandList](API\Runtime\RHI\FRHICommandList) & RHICmdList, const [FSceneView](API\Runtime\Engine\FSceneView) & View, const FIntRect & ViewRect, FIntRect * OutScissorRect ) const